The present invention relates to a thermoforming press.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
German Offenlegungsschrift DE 24 52 486 C2 describes a process to make a hardened steel article by heating a hardenable steel blank to hardening temperature and then placing it in a press tool in which the blank is deformed and simultaneously rapidly cooled to obtain a martensitic and/or bainitic structure, while the blank remains in the press tool. Cooling is implemented indirectly via cooling channels for circulation of a coolant. Provision of such cooling channels is difficult to realize and costly.
German Offenlegungsschrift DE 26 03 618 describes a thermoforming press with upper and lower dies having incorporated therein concentric annular grooves which are fluidly connected to channels extending through the dies. As a result, coolant flows through these channels into the annular grooves for direct contact with a steel article to be hardened. This type of press is also complex and requires long process times and extensive maintenance.
It would be desirable and advantageous to provide an improved thermoforming press to obviate prior art shortcomings.